Current-converting apparatus.



L. P. CRECELIUS.

CURRENT CONVERTING APPARATUS.

APPLICATION FILED was 9.1913.

1 ,1 92,393. Patented July 25, 1916.

3 SHEETS-SHEET I.

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L. P. CRECELIUS.

CURRENT CONVERTING APPARATUS.

APPLICATION FILED JUNE 9. 1.913.

Patented July 25,1916.

3 SHEETS-SHEET 2.

L. P. CRECELIUS.

CURRENT CONVERTING APPARATUS.

APPLICATION FILED JUNE 9.1913.

Patented July 25, 1916.

3 SHEETS-SHEETS.

.5 Vim LAWRENCE P. CRECELIUS, OF CLEVELAND, OHIO.

CURRENT-CONVERTING APPARATUS.

Specification of Letters Patent.

Patented July 25, 1916.

Application filed June 9, 1913. Serial No. 772,550.

To all whom it may concern:

Be it known that I, Lnwnnncn P. CRE- onLrUs, a citizen of'the United States, re siding at Cleveland, in the county of Guyahoga and State of Ohio, have invented a certain new and useful Improvement in (hirrent-Converting Apparatus, of which the following is a full, clear, and exact description.

This invention relates to current converting apparatus of the mechanical type wherein a resistance or a suitable series of resistance sections have their terminals connected to a circuit which supplies direct current, and are connected between their terminals, by means of spaced taps, to the bars of a commutator which is engaged by relatively rotating brushes to which alternating current terminals are connected.

The main object of the present invention is to provide a unitary structure in which are incorporated the resistance sections and all stationary and rotary parts of the commutator, brushes and collector rings, and preferably also the motor which drives the rotating parts and which may be utilized for ventilating or cooling the resistance sections.

Further objects are to provide a unitary structure for the purpose stated, which is light in weight and wherein all parts are well supported and compactly arranged, and the resistance sections are effectively cooled.

The invention may be briefly summarized as consisting in certain novel details of construction and combinations and arrangements of parts which will be described in the specification and set forth in the appended claims.

In the accompanying sheets of drawings wherein I have shown the preferred embodiment of my invention, Figure 1 is a side view of the apparatus in its entirety with parts in section, and with other parts broken away for the sake of clearness; Fig. 2 is a top plan view of the same with parts in section, and with other parts broken away Fig. 3 is a sectional view substantially along the line 33 of Fig. 1, looking forwardly or in the direction indicated by the arrow, the lower part of the apparatusbeing broken away; Fig. 4 is a front view with parts in section, and with other parts broken away; Fig. 5 is a diagrammatic view of the preferred electric circuits; and Fig. 6 is a similar View showing a modification.

In the preferred embodiment of my invention, the supporting parts of the apparatus include a rectangular frame 10 which may and preferably is composed of light structural material, and is inclosed within suitable side and top plates 11 which may be provided with a suitable number of ventilating openings or slots 12.

Arranged within the frame l0 and supported therefrom on suitable frame work, or on a subframe which may be designated as a whole by the reference character 13 is the resistance part of the apparatus which in this case consists of a large number of resistance grids 14, which as here shown are arranged vertically in two vertical rows or tiers, and are arranged and directly supported on suitable horizontally extending rods 15 mounted in the frame work 13. These resistance grids which are traversed by the direct current, may all be connected in series, as shown in Fig. 5, or if desired, the resistance members may be connected in series parallel arrangement as shown in Fig. (3, although the arrangement shown in Fig. 5 is preferable. It is not essential to the present invention that the resistance members consist of grids, for if desired, resistance members in other forms may be em ployed, but the grids are very effective for my purpose, and I have illustrated the same in this case. In any event, these resistance members are very firmly or rigidly supported, and compactly arranged in the supporting framework.

At the front end of the frame 10 is a front plate 16, and at the rear end of the frame is a relatively small plate 17, both of which plates are provided with bearings in the vertical center plane of the apparatus for a rotary motor driven shaft 18, which extends horizontally through the major portion of the apparatus.

Supported by this front plate 16, and on the front face thereof is a commutator 19, the bars or segments of which are rigidly supported in fixed position, concentrically with respect to the axis of the shaft 18, by an insulated multi-part clamping ring 20, which surrounds the commutator, and by suitable bolts or studs 21 which securely fasten said ring to the front side of the plate 16. The bars of the commutator are connected by taps 22 to different points of the resistance let, these taps being preferably carried forwardly through the resistance supporting frame 1 3 in suitable conduits arranged near the center plane of the apparatus on opposite sides of the shaft 18, and at the front end of the apparatus the taps are distributed as best shown in Figs. 2, and l, and pass through circularly or annularly arranged series of openings in the front plate 10, and thence pass radially inward to the commutator, to the bars of which the taps are severally or consecutively connected.

b'ccured to the end of the shaft which projects beyond the front plate 16 is a brush and collector ring support 25, which is formed of fiber or other similar insulating material. The inner part of this support has fixed to it at diametrically opposite points, two rotating brush holders 26 carrying carbon brushes 2? which engage the inner periphery or surface of the commutator, and are pressed outward against the commutator by the action of centrifugal force, and by suitable springs carried by the brush holders.

Fixed to the insulating support 25 outwardly from the brush holders, are two collector rings 28, which are'engaged by brushes 29 carried by brush holders 3O sup ported by a housing 31 which incloses all parts of the apparatus on the outer side of the plate 16.

The shaft 18 is adapted to be driven by an electric motor 32 which is arranged at the rear end of the frame 10 and has its shaft coupled by a coupling 33 to the shaft 18. This motor is preferably supported by suitable brackets 3f projecting outwardly from the rear end of the main frame 10, as shown particularly in Fig. 1. Just inside the main frame 10, and at the rear of the resistance members 14, the shaft is provided with a fan 35, the blades of which a re arranged as to cause a strong draft forwardly over the resistance members so as to prevent the same from becoming overheated. The air can escape from the inclosing parts through openings 12, and through the bottom portion of the apparatus, which may be left open.

In 5, the resistance sections are arranged in one series circuit, as previously stated, and are supplied with direct current by leads here designated 36 and 37. Upon the rotation of the brushes 2 7 alternating current is taken off from the brushes 29, which can be connected to the primary of a transformer 38, there being one alternating irrent cycle at each complete rotation of the motor driven brushes. By properly spacing the taps or otherwise varying the potential drop between taps, practically a true sine wave can be obtained. A Wave form which approximates the sine wave can be secured by having less potential drop between the taps near the outer terminals than near the center of the resistance. This can be accomplished either by varying the spacest at its ends, and gradually decreases in size toward the center. This serves to indicate that the ohmic resistance of the end sections is less than resistance of the sections remote from the ends.

In Fig. 6, the resistance members are arranged in series parallel arrangement, the current passing between the direct current leads in two parallel paths. .Vith this arrangement, the results are substantially the same as with the arrangement shown in Fig. 5, although the latter is preferable, as it requires less resistance or resistance members than the arrangement shown in Fig. 6, and is more economical than the latter.

The current converting apparatus above described may be used for a variety of purposes, but is particularly effective for use in converting direct current to alternating current for rail bonding purposes. The arrangement of all the parts in the form of an extremely light and compact unit, and the rigid and effective supporting of the parts within the structure is particuarly important when the apparatus is used as part of the rail bonding equipment, in view of the fact that the apparatus must be moved frequently from point to point. The unit feature admits of the apparatus being moved about easily and without much loss of time. It may be said further that this apparatus is very much lighter in weight and far less expensive to manufacture than a rotary converter of the same capacity.

Having thus described my invention, what I claim is:

1. In a current converting apparatus, an inclosed frame, a resistance supported by the frame within the inclosure, a commutator supported in fixed position at one end of the frame, said resistance adapted to be connected at the outer terminals thereof to the positive and negative sides of a direct current circuit, taps connecting the bars of the commutator to spaced points of the resistance, a shaft extending through the frame, a pair of brushes engaging the bars of the commutator and connected to the shaft so as to be rotated thereby, and a motor supported at the opposite end of the frame and connected to said shaft for drivsupported Within the inclosure, a stationary commutator at one end of the inclosure, taps connecting the bars of the commutator with spaced points of the resistance, brushes engaging the commutator, a shaft for driving the brushes, and a motor located outside of the inclosure and having its shaft in alinement Withand coupled to said first named shaft, all said parts of the apparatus being in the form of a self-contained portable unit.

3. In a current converting apparatus, an inclosure, a resistance supported therein, a stationary commutator at one end of the inclosure, the bars of the commutator being connected to spaced points of the resistance,

a pair of rotating brushes engaging the com mutator, a shaft extending through the inclosure, a driving motor at the opposite end of the inclosure, said shaft at one end being connected to the brushes and at its opposite end being connected to the motor, all of said parts being in the form of a self-contained portable unit.

In testimony whereof, I hereunto affix my signature in the presence of two Witnesses.

LAWRENCE P. CRECELIUS.

Witnesses:

E. B. GILCHRIST, A. F. Kwrs.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner 01' Patents, Washington, D. Go 

